var button = {
	options : {
		tooltip: "Vai alla Visualizzazione Precedente",
		iconCls: "zoomprevious",
		//enableToggle: true,
		disabled: true,
		pressed: false,
		id: "zoomprevious"
	},
	create : function(options) {
		// create a navigation history control
		var historyControl = null; 
		var controls = CWN2.base.map.getControlsByClass("OpenLayers.Control.NavigationHistory");
		if (controls.length === 0) {
			historyControl = new OpenLayers.Control.NavigationHistory();
			CWN2.base.map.addControl(historyControl);						
		} else {
			historyControl = controls[0];
		} 			
		options.control = historyControl.previous;
		return new GeoExt.Action(options);
	}
};

CWN2.ToolbarBuilder.itemDefs[button.options.id] = button;

